Static resource allocation of advanced reservation requests in elastic optical networks

Considering the flexibility characteristic of advanced reservation (AR) requests, the problem of static routing, modulation, spectrum, and time assignment (RMSTA) of AR requests in elastic optical networks is studied in this paper, in order to deploy the spectrum resource economically and enable more requests to be served. The multi-objective integer linear program (ILP) model, which can minimize the maximum utilized frequency and time slot indices as well as find a trade-off between them, is used to formulate the RMSTA problem. Then the proportion optimal RMSTA (PO-RMSTA) heuristic algorithm with three sorting strategies is proposed to get the sub-optimal solutions. The PO-RMSTA algorithm and sorting strategies, ascending order of elastic time (AET), descending order of data volume (DDV), and ascending order of alternative schemes (AAS), are simulated in our work and proved to obtain the approximate optimal solutions. The sorting policy AET achieved the best performance when minimizing the maximum utilized frequency slot index, whereas the sorting policy DDV worked best when minimizing the maximum utilized time slot index. As for the compromise between two indices, both AET and AAS provided satisfying results.